#define _CRT_SECURE_NO_WARNINGS 1
#include<iostream>
using namespace std;
const int N = 1010;
int n, m;
int f[N][N];
char a[N], b[N];
int main()
{
    ios::sync_with_stdio(false); cin.tie(nullptr);
    cin >> n >> m;
    cin >> a + 1 >> b + 1;
    for (int i = 1; i <= n; i++)
    {
        for (int j = 1; j <= m; j++)
        {
            f[i][j] = max(f[i - 1][j], f[i][j - 1]);
            if (a[i] == b[j]) f[i][j] = max(f[i][j], f[i - 1][j - 1] + 1);
        }
    }
    cout << f[n][m];
    return 0;
}